China’s foreign minister said on Monday that he hoped construction of a new Thai railway could start immediately to give Thailand better access to Chinese markets.

Wang Yi is in Bangkok on an official visit to strengthen political and economic relations, which have expanded in recent years as China has sought to spread its influence and Thailand’s military government has loosened ties with the United States.

The joint Thai-Chinese plan for a new US$5.3 billion railway from Bangkok to the northeast has been repeatedly delayed, largely over differences about financing, but last month Thai Prime Minister Prayuth Chan-ocha issued a special order to expedite construction.

The railroad is part of China’s belt and road infrastructure project allowing cross-border development and connectivity among Asian countries, Africa, China and Europe.

Meanwhile, Wang said Beijing wanted to maintain stability in the contested South China Sea.

His remarks came as US President Donald Trump reportedly gave the green light to the Pentagon’s plan to conduct more patrols in the disputed waters on a “very routine, very regular” basis to challenge China’s expansive claims and increasing assertiveness in the region. A head of a regional meeting of Southeast Asian countries in Manila next month, Wang said China would like to “maintain stability in the South China Sea, abiding by the terms that have been agreed on the Declaration of Conduct and Code of Conduct”.

China and Southeast Asian countries are believed to be pressing ahead with a long-stalled South China Sea code of conduct after agreeing on the framework in May.

China claims most of the energy-rich sea through which about US$5 trillion in ship-borne trade passes every year. Brunei, Malaysia, the Philippines, Taiwan and Vietnam also have claims.

But Vietnam has reportedly suspended drilling activities in the contested waters because of threats from Beijing.

The BBC reported on Monday that Hanoi ordered Spanish oil company Repsol, which started gas-drilling operations in an area about 400km off Vietnam’s southeast coast last month, to leave the zone.

Citing an unnamed industry source, the report said Beijing had “threatened to attack Vietnamese bases in the Spratly Islands if the drilling did not stop”.

Ties between China and Vietnam have been strained again over the energy exploration in the area, with Central Military Commission vice-chairman General Fan Changlong cutting short an official trip to Vietnam last month.

Tensions in the South China Sea also resurfaced after the US Navy conducted two freedom of navigation patrols in the waters in May and this month, moves Beijing condemned as undermining regional stabily and increasing uncertainties over China-US relations.

Chinese analysts said Washington’s plan to send US Navy ships to the waters would further antagonise Beijing and fuel tensions in the region.

Also on Monday, Thai Foreign Minister Don Pramudwinai said there were “no obstacles” to the relationship between the two countries.

Thailand this year approved the purchase of more than US$500 million of Chinese submarines, tank and helicopter.